The present invention relates generally to the field of surgical and interventional radiological techniques and more particularly to a method and apparatus for affixing an endoluminal device to the walls of tubular structures within the body. Examples of such structures are the biliary ductal system, the excretory system and blood vessels such as the aorta and the inferior vena cava.
One technique for permitting the repair of aortic aneurysms involves the utilization of a spring-like wound wire which provides the force to engage a plurality of anchoring pins to the vessel wall as exemplified in Choudbury, U.S. Pat. No. 4,140,126. Inherent in the operation of this device is the abrupt nature of its engagement with the wall of the healthy vessel and its capability of only being engaged or disengaged therefrom by the force of the spring-like would wire.
Additionally, a tubular graft could be implanted within a preselected blood vessel by inserting the graft endwise and axially through the blood vessel and secured into place therein by the engagement of surgical staple-like clips with the vessel wall as shown in Taheri, U.S. Pat. No. 4,872,874. The staple-like clips are engaged with the vessel wall due to the inflation of a balloon which is then removed from the vessel after engagement. Once the clips are engaged with the vessel, the graft is permanently inserted in the vessel and it cannot easily be moved without extensive damage to the surrounding vessel and tissue.
The main problem with securing endoluminal medical devices to a tubular wall is the risk of misplacement which can lead to catastrophic results such as the complete occlusion of the tube or possibly even the migration of the device to an undesired location. Additionally, damage to the tubular wall can occur when a device is being positioned within the tube if the apparatus used to secure the device employs exposed barbs or staples. Because of these problems, extensive fluoroscopic examination is required to ensure the correct placement of the device to minimize the risk of misplacement and tissue damage.
What is desired is a method and apparatus for repositionable replacement of an endoluminal medical device within the tubular structures of the body. The utilization of an inflatable balloon cuff provided with a plurality of small pockets or recesses arrayed on its outer surface in which a plurality of wall engagement barbs are secured satisfies this desire. When the cuff is not fully inflated, the barbs are disposed fully within the recesses and are prevented from engaging the tubular wall which precludes any possible damage to the walls.
At low levels of inflation of the cuff, only the smooth outer surface contacts the structure walls which allows the cuff to be moved and repositioned without damaging the surrounding tissue. In this way, the medical device can be positioned at the optimal location within the tubular structure. It can then be permanently affixed to the wall by fully inflating the cuff thereby causing the barbs to deploy and engage the wall.
Accordingly, it is an object of the present invention to provide a method and apparatus for affixing an endoluminal device to the walls of tubular structures within the body which satisfies the aforementioned desire. Also, it is an object of the present invention to provide a method in which medical devices can be affixed to tubular structure's walls without causing damage thereto and to prevent migration of the device after it has been affixed.